blimp-1 expression as an exhaustion transcription factor in chronic lymphocytic leukemia

Background: previously, it was shown that exhausted cd4+ and cd8+ t cells in chronic lymphocytic leukemia (cll) co-express the two immune-inhibitory receptors, tim-3 and pd-1. present study investigated the expression of blimp-1, a transcription factor involved in t cell exhaustion, in patients with cll. materials and methods: peripheral blood mononuclear cells were collected from 25 untreated cll patients and 15 sex- and age-matched normal subjects. cll patients were clinically classified according to the rai staging system. the relative expression of blimp-1 mrna was determined by quantitative real time polymerase chain reaction (qrt-pcr) after normalization with β-actin. results: expression of blimp-1 mrna was much higher in cll patients than in normal controls (p=0.001). moreover, blimp-1 was more expressed in patients with advanced clinical stages of cll compared to those with early stages of the disease (p=0.01). interestingly, the blimp-1 expression was correlated with the frequencies of exhausted tim-3+/pd-1+/cd4+ and tim-3+/pd-1+/cd8+ t cells in cll patients. conclusion: our results highlight the role of blimp-1 transcription factor in t cell exhaustion of cll.